As a method of measuring resistivity of a single crystal silicon wafer, a method of measuring capacitance-voltage (C-V) characteristics thereof has hitherto been known. For measuring the C-V characteristics, a Schottky barrier junction is formed on a surface of a single crystal silicon wafer to be measured, and then a reverse bias voltage is applied thereto while the voltage is continuously varied to expand a depletion layer in the single crystal silicon wafer, to thereby vary capacitance of the depletion layer. For forming a Schottky barrier junction on a surface of a single crystal silicon wafer, for example, a mercury electrode is used.
Mercury probes for measuring the C-V characteristics of a single crystal silicon wafer using a mercury electrode have been known. For example, Patent Document 1 discloses a mercury probe for measuring electrical characteristics of a single crystal silicon wafer using a top contact mercury probe, enabling the measurement of the electrical characteristics of the single crystal silicon wafer without contamination and surface defects of the wafer. In the mercury probe, mercury serving as an electrode is put in contact with the single crystal silicon wafer from above.
Moreover, Patent Document 2 discloses a mercury probe having an upward facing mercury electrode disposed to interface with a main surface of a semiconductor single crystal silicon wafer held upside down.
In the case where the single crystal silicon wafer to be measured is n-type, the C-V characteristics can be measured by preliminarily oxidizing the surface of the single crystal silicon wafer to form a thin silicon oxide film thereon and then putting a mercury electrode into contact with the silicon oxide film.
As a method of forming a thin silicon oxide film on a surface of a single crystal silicon wafer, for example in Non Patent Document 1, there is disclosed a method involving immersing a wafer in a solution containing an oxidant such as hydrogen peroxide for a few minutes, followed by rinsing and drying. Further, in Patent Document 3, there is disclosed a method of oxidizing a surface of a single crystal silicon wafer with ozone gas, involving exposing the single crystal silicon wafer to ultraviolet rays in an atmosphere containing oxygen.